Abstract
The genus Sorbus consists of small to medium-sized trees
primarily found in coastal areas, with three European hotspots for
diversification: Fennoscandia, South-East Europe, and Britain. Taxonomic
classification of Sorbus in Europe is still unresolved, and this
study aims to address this issue by examining the pollen morphology of
different Sorbus hybrids. Pollen morphology of 16 specimens from
13 species of Sorbus , Aria and Hedlundia , some of
which are common, while others are endemic and listed as threatened
species, were studied. Measurements of the polar and equatorial axis of
all pollen show that there are variations in pollen size and shape among
different hybrids, with correlation between polyploidy levels and the
width of the pollen. Surface structures of pollen were observed using
SEM. Principal Component Analysis (PCA) was performed to analyze the
pollen characters, and the results show that it is possible to separateAria from Sorbus and Hedlundia based on the length
of the pollen grain, while the number of perforations is important for
classification within Hedlundia . The study concludes that pollen
morphology can be a useful tool for distinguishing between differentSorbus hybrids and can thus aid in understanding their past
distributions.